Snap-cure flexible electrically conductive one component (1K) epoxy adhesive composition

Abstract

The present invention relates to an electrically conductive composition comprising a) from 5 to 25% by weight of the total weight of the composition of a cycloaliphatic epoxide resin; b) from 0.05 to 10% by weight of the total weight of the composition of a vinyl ether; c) from 0.1 to 0.45% by weight of the total weight of the composition of an onium salt; d) from 0.01 to 10% by weight of the total weight of the composition of a radical initiator; e) from 45 to 85% by weight of the total weight of the composition of electrically conductive particles; and f) from 0.1 to 10% by weight of the total weight of the composition of an organic solvent. The composition can be used as an adhesive in the electronic applications, especially as an adhesive in the shingle module photovoltaic applications.

What is claimed is: 
     
         1 . An electrically conductive composition comprising
 a) from 5 to 25% by weight of the total weight of the composition of a cycloaliphatic epoxide resin;   b) from 0.05 to 10% by weight of the total weight of the composition of a vinyl ether;   c) from 0.1 to 0.45% by weight of the total weight of the composition of an onium salt;   d) from 0.01 to 10% by weight of the total weight of the composition of a radical initiator;   e) from 45 to 85% by weight of the total weight of the composition of electrically conductive particles; and   f) from 0.1 to 10% by weight of the total weight of the composition of an organic solvent.   
     
     
         2 . The electrically conductive composition according to  claim 1 , wherein the cycloaliphatic epoxide resin contains at least one epoxy cyclohexane ring and is selected from the group consisting of bis(7-oxabicyclo[4.1.0]hept-3-ylmethyl)adipate, (3′,4′-epoxycyclohexane)methyl 3,4-epoxycyclohexylcarboxylate, 7-oxabicyclo[4.1.0]heptan-3-ylmethyl acrylate, 3,4-epoxycyclohexane carboxylic acid methyl ester, bis(oxiran-2-ylmethyl) cyclohexane-1,2-dicarboxylate, and mixtures thereof. 
     
     
         3 . The electrically conductive composition according to  claim 1 , wherein the cycloaliphatic epoxide resin is present from 8 to 20% by weight of the total weight of the composition. 
     
     
         4 . The electrically conductive composition according to  claim 1 , wherein the vinyl ether is selected from the group consisting of 4-hydroxybutylvinylether, diethylene glycol divinylether, cyclohexane-dimethanol divinylether, dodecylvinylether, cyclohexyl divinylether, 2-ethyhexyl vinyl ether, dipropyleneglycol divinylether, hexanediol divinylether, octadecyl vinyl ether, butanediol divinylether, triethyleneglycol divinylether and mixtures thereof. 
     
     
         5 . The electrically conductive composition according to  claim 1 , wherein the vinyl ether is present from 0.1 to 5% by weight of the total weight of the composition. 
     
     
         6 . The electrically conductive composition according to  claim 1 , wherein the onium salt is selected from the group consisting of cumyltolyl iodonium tetrakis(pentafluorophenyl)borate, [4-(acetyloxy)phenyl]methyl(phenylmethyl)sulfonium hexafluorophosphate, (4-hydroxyphenyl methyl(1-naphtalenylmethyl)sulfonium hexafluorophosphate, 4-(acetoxyphenyl)benzyl(methyl)sulfonium, tetrakis(pentafluorophenyl)borate, and mixtures thereof. 
     
     
         7 . The electrically conductive composition according to  claim 1 , wherein the onium salt is present from 0.15 to 0.4% by weight of the total weight of the composition. 
     
     
         8 . The electrically conductive composition according to  claim 1 , wherein the radical initiator is present from 0.02 to 5% by weight of the total weight of the composition. 
     
     
         9 . The electrically conductive composition according to  claim 1 , wherein the electrically conductive particles are selected from the group consisting of silver, nickel, carbon, carbon black, graphite, graphene, copper, gold, platinum, aluminium, iron, zinc, cobalt, lead, tin alloys, silver coated nickel, silver coated copper, silver coated graphite, silver coated polymers, silver coated aluminium, silver coated glass, silver coated carbon, silver coated boron nitride, silver coated aluminium oxide, silver coated aluminium hydroxide, nickel coated graphite, and, mixtures thereof, electrically conductive filler is selected from the group consisting of silver, carbon black, graphite, graphene, copper, silver coated nickel, silver coated copper, silver coated graphite, silver coated polymers, silver coated aluminium, silver coated glass, silver coated carbon, silver coated boron nitride, silver coated aluminium oxide, silver coated aluminium hydroxide, nickel coated graphite, and, mixtures thereof. 
     
     
         10 . The electrically conductive composition according to  claim 1 , wherein the electrically conductive particles are present from 63 to 78% by weight of the total weight of the composition. 
     
     
         11 . The electrically conductive composition according to  claim 1 , wherein the organic solvent is a polar aprotic solvent or a protic solvent or mixtures thereof. 
     
     
         12 . The electrically conductive composition according to  claim 1 , wherein the organic solvent is present from 0.15 to 5% by weight of the total weight of the composition. 
     
     
         13 . A cured product of the electrically conductive composition according to  claim 1 . 
     
     
         14 . A photovoltaic module comprising a series-connected string of two or more solar cells in a shingle pattern having an electrically conductive bonding between said two or more solar cells, wherein said electrically conductive bonding is formed with an electrically conductive composition according to  claim 1 . 
     
     
         15 . The photovoltaic module according to  claim 14 , wherein said electrically conductive composition is applied by dispensing, jetting or printing.